精品感谢下载载ⅠChoose one which is the best answer in each question(40 × 1 point = 40 )1. Immunological unresponsiveness to self antigens is called: ( A) A Tolerance B Tolerogen C Memory D Acquired immunity 2. The signal transduction molecules associated with BCR are (B ) A. CD21 and CD81. B. Ig αnd Ig βCD79a,b C. IgD and IgM. D.ITAMs and ITIMs. 3. T cells are MHC-restricted in their ability to respond to antigen because (D ) A. all antigen must be processed and presented to activate lymphocytes. B. during an infection, all cells in the body present antigen on MHC Class I. C. MHC binds antigen more specifically than TCR does. D. TCR must recognize both antigen and MHC molecules. 4. An antibody Fab contains ( A B) A. complementarity determining regions. B. H and L chain variable regions. C. one antigen binding region. D. one H-L interchain disulfide bond. 5 Positive selection in the thymus is mediated by: ( A ) A Thymic epithelial cells. B Macrophages. C Dendritic cells. D B-cells. 精品感谢下载载6. Type Ⅳ hypersentivity is often referred to as: ( B ) A. Immediate hypersensitivity B. Delayed hypersensitivity C. Cytotoxic hypersensitivity D. Allergic hypersensitivity 7. Type Ⅱhypersentivity is often referred to as: ( C ) A. Immediate hypersensitivity B. Delayed hypersensitivity C. Cytotoxic hypersensitivity D. Allergic hypersensitivity 8. Naive B cell expresses ( C ) A. IgA alone B.IgA and IgG C IgM +IgD D.IgE and Ig 9. T cell-derived cytokines ( D ) A. are antigen-specific products of T cell activation B. are stored in the resting T cell and released on activation C. are MHC-restricted in their effects D. influence the class of antibodies produced by B cell 10. Neutrophils are...